Hydraulic Intensifier Construction, Working Principle and Equation

What is A Hydraulic Intensifier?

An intensifier or pressure booster is an internal power regenerator device used to increase fluid pressure, usually oil or water. Intensifiers may be either hydraulically or pneumatically operated, the advantage of the latter being that no power unit is required since the air can be taken from the general supply or storage tank. This hydraulic machine increases the intensity of pressure of a given liquid with the help of hydraulic energy of low-pressure liquid of large quantities. Such a device is needed when hydraulic machines such as hydraulic press require water at very high pressure, which cannot be obtained from the main supply directly. By means of an intensifier, it is possible to raise the intensity of pressure as high as 160 MN/m²

The hydraulic pressure intensifier finds its practical application in cases where a low-pressure liquid must be converted into a liquid of considerably higher pressure. This device becomes essential when hydraulic machinery, including hydraulic presses, cranes, and lifts, requires a liquid at extremely high pressures that cannot be directly obtained from a pump. It is placed between the primary power source of the hydraulic system (the pump) and the machinery itself, such as a press or crane. The hydraulic intensifier ensures the delivery of the necessary high-pressure liquid for smooth operation. Its mode of operation can be compared to that of a step-up electrical transformer.

🔗Construction and working of Hydraulic Torque Convertor

Various types of hydraulic intensifier options exist, each classified based on distinct factors. This classification encompasses the single-acting intensifier, double-acting intensifier, hydro-pneumatic intensifier, and the innovative free piston type, among others.

How Does Hydraulic Intensifier Work?

Construction of hydraulic intensifier

The figure shows parts of a hydraulic pressure intensifier. Hydraulic intensifier consists of the following major components.

In a hydraulic pressure intensifier, the key components comprise the fixed ram, sliding cylinder, and fixed cylinder.

Fixed ram: It is the innermost and smallest component of the hydraulic intensifier. It serves as a pathway for high-pressure water flow towards the machine.

Sliding cylinder: The inverted sliding cylinder, positioned between the fixed ram and fixed cylinder, encloses the fixed ram and holds the pressurized water. This is the sole mobile part of the device, effortlessly sliding in response to hydraulic forces. It facilitates the conveyance of pressurized water to the machine.

Fixed cylinder: Surrounding the sliding cylinder is the larger fixed inverted cylinder, forming the outermost layer of the hydraulic intensifier. This container accommodates water sourced from the primary supply, maintained at a lower pressure than the water in the sliding cylinder.

Valves: Intensifiers usually have four valves - inlet and outlet valves for fixed and sliding cylinders.

Working of hydraulic intensifier

Here we are going to explain the simple single-acting intensification process.

For easy understanding, we can assign the names V1, V2, V3, and V4 to the valves involved in the hydraulic intensifier system.

Valve V1 regulates the flow of low-pressure liquid from the supply to the sliding intensifier cylinder, ensuring its controlled entry.

Valve V2 governs the release of high-pressure liquid, directing it towards the designated machine for its intended operations.

Valve V3 facilitates the discharge of low-pressure liquid from the fixed intensifier cylinder, releasing it to the exhaust.

Valve V4 controls the entry of low-pressure liquid from the supply to the fixed cylinder.

At the start of the cycle, with the sliding cylinder resting at the bottom most position of its stroke, the fixed cylinder contains a reservoir of low-pressure liquid. During this phase, valves V2 and V4 are closed, effectively isolating their respective pathways. Conversely, valve V1 is opened, allowing the influx of low-pressure liquid into the sliding cylinder. Simultaneously, valve V3 is also opened, enabling the discharge of low-pressure liquid from the fixed cylinder to the exhaust. As a result, the sliding cylinder ascends in motion. As the sliding cylinder reaches its uppermost position, the internal cavity becomes filled with low-pressure liquid.

Once the sliding intensifier cylinder reaches its topmost position, valves V1 and V3 are closed, while valves V2 and V4 are opened. This allows low-pressure liquid from the supply to enter the fixed cylinder through valve V4. As a result, the sliding cylinder is compelled to move downwards under the influence of hydraulic forces. During this descent, the water within the sliding cylinder undergoes compression, leading to a proportional increase in pressure. Consequently, high-pressure water is expelled from the sliding cylinder through the fixed ram via valve V2, ultimately supplying the machine with the required hydraulic power.

This cyclic operation process is subsequently repeated, ensuring the continued functioning of the hydraulic intensifier.

Hydraulic Intensifier Working Principle

Consider, 

p1 = Pressure intensity of low-pressure liquid from the supply in the fixed cylinder,

A1 = Cross-sectional area of sliding cylinder,

p2 = Intensity of high-pressure liquid in the fixed ram

A2 = Cross-sectional area of the fixed ram.

The downward force exerted by the low-pressure liquid on the sliding cylinder = p1 × A1

The upward force exerted by the high-pressure liquid on the sliding cylinder = p2 × A2

The upward and downward forces must be equal to achieve equilibrium at any position. Equating the upward and downward forces, we have p1 × A1 = p2 × A2 

By neglecting the impact of friction, the theoretical intensified pressure can be determined using the hydraulic intensifier formula p2 = p1A1/A2

Since the area is proportional to the square of the diameter, this relationship highlights that pressure intensifiers magnify pressure in direct proportion to the square of the inverse ratio of diameters. This shows adequate hydraulic amplification.

🔗Application, advantages and limitations of Hydraulic Intensifier

How To Select the Right Hydraulic Intensifier?

Selecting the right hydraulic intensifier for an application requires careful consideration of several factors, such as:

Pressure requirement: The pressure requirement of the application is the most important factor to consider when selecting a hydraulic intensifier. It is essential to ensure that the hydraulic intensifier can provide the required pressure for the application.

Flow rate requirement: The flow rate requirement of the application is another important factor to consider when selecting a hydraulic intensifier. It is necessary to ensure that the hydraulic intensifier can provide the required flow rate for the application.

Type of hydraulic intensifier: The appropriate type of hydraulic intensifier needs to be selected for the application, such as single-acting or double-acting, hydropneumatics, free piston, etc.

Space requirements: It is important to ensure that the hydraulic intensifier can fit into the available space.

Operating conditions: The hydraulic intensifier must be able to withstand the operating conditions, including temperature, pressure, and environment, of the application.

Maintenance requirements: It is crucial to ensure that the hydraulic intensifier is easy to maintain and repair.

Cost: It is necessary to ensure that the hydraulic intensifier fits within the budget and provides the best value for money.